Dynamic Research Of 3-RRRT Parallel Manipulator Based On MATLAB

In this paper the kinematics and dynamics of the 3-RRRT parallel manipulator have been researched.The main contents contained: the kinematics modeling,the numerical simulation of kinematics and dynamics and the optimization of configuration.The 3-RRRT parallel manipulator is composed of a fixed platform and a moving platform which are connected through three branched-chains,each branch consists of three revolute pairs with R said and a hooke joint with T said.Through analyzing the degrees of freedom of the 3-RRRT parallel manipulator,we find that its moving platform can only move in the space along the three axes translationally,so the number of degrees of freedom is three.Comparing with the serial robots in the past,this new robot shows high speed,high precision,large bearing and a number of advantages,making it widely used in the engineering industry,such as parallel machine tools,food sorting facilities.This 3-RRRT parallel manipulator can be applied to food sorting process.Through the kinematics and dynamics analyses of this robot,we can make it become the prototype and the basis of the later research of spatial parallel manipulator with high-performance,such as parallel machine tools,micro robots.Firstly,according to the characteristics of the 3-RRRT parallel manipulator mechanism,the kinematic equation is established by using D-H coordinate method and homogeneous coordinate transformation.The reverse displacement solution was got by using analytical method when the moving platform of the 3-RRRT parallel manipulator was under a certain position and posture.Each branch chain of the parallel manipulator has two groups of reverse displacement solution.The direct solution of the 3-RRRT parallel manipulator was solved by using numerical method and the correctness of the solution was verified by MATLAB software programming.Secondly,on the basis of kinematics analysis,the dynamic model of the 3-RRRT parallel manipulator was established.By using Newton-Euler dynamics method,the acceleration,inertial force,joint force and the driving force were solved by using the recursive formula.Furthermore,under the condition of the trajectory of the moving platform has been planned,the driving force of each branch chain has been simulated by the MATLAB software programming.Finally,to reduce the energy consumption of the system,the configuration optimization of the system has been conducted on the basis of the kinematic and dynamic model.By using Newton-Euler Dynamics method,we make the parallel manipulator become a open-chain structure through a branch cut from a joint.Through Newton-Euler algorithm,the inertia force of each joint can be solved,which can provide theoretical basis of the flexible analyses of the parallel robot in the future.